Created by the late Stephen J. Cannell, the superhero comedy-drama starred William Katt, the late Robert Culp, and Connie Sellecca. The premise: Ralph Hinkley, a high school teacher, is given a special suit by aliens from outer space. However, there's one problem: he lost the instruction book. Ralph then teams up with Bill Maxwell, a hard-nosed FBI agent, and together with Ralph's attorney girlfriend (later wife) Pam Davidson, they wage a war on crime, corruption, and injustice -- all the while trying to figure out the suit's capabilities.
Aired on ABC from 1981 to 1983, The Greatest American Hero may not have been as popular as The Rockford Files or The A-Team, but the show has maintained a devoted following over the years -- most notably due to 'Believe it or Not', the theme song sung by Joey Scarbury, as well as marathons on the SyFy channel and DVD releases.
There was a 1986 pilot entitled 'The Greatest American Heroine', where Ralph passed on the suit to another schoolteacher, but it was never picked up as a series.